lucky lottery id generator

package main

import (
	"fmt"
	"math/big"
	"math/rand"
)

func main() {
	tx := "00000000000000000002bf59c3d819e4666909512803cf28113ff09849b4545e"
	total := int64(10) // type in maxmium lottery nubmer here

	fmt.Printf("lucy lottery id: %d\n", Rand(tx, total))
}

// @param tx:
//  from site: https://btc.com/block 
//  The hash of the first block generated after UTC 08:00AM. On 2018-10-11, for example tx is 00000000000000000011f41d5df213f232c1778730e834635eb836276fc184bf
//  which from block: https://btc.com/00000000000000000011f41d5df213f232c1778730e834635eb836276fc184bf
// @param total 
//  the total luck lottery numbers generated duratation the non-mining minutes
//
func Rand(tx string, total int64) int64 {
	v, _ := big.NewInt(0).SetString(tx, 16)
	seed := v.Int64() // ignore overflow
	source := rand.NewSource(seed)
	r := rand.New(source)

	return r.Int63n(int64(total)) + 1 // +1 because our lottery numbers starts from 1
}